Working with Breakpoints 
The execution of an application is a set of steps, performed in a specific order. A breakpoint causes the execution of the application to suspend at the location where the breakpoint is set. The execution suspends at the beginning of the step. To perform the step, the modeler needs to use the stepping functions. For more information, see Stepping Through the Application.
Note
A breakpoint always causes the application execution to stop. For example, if there is a breakpoint in a model referenced from the application (a nested model or a modeled service), the runtime suspends when the breakpoint in the referenced model is reached.
You can add breakpoints to a model either before running the application, or dynamically, when the application is already running in debug mode.
You can set breakpoints on the Design board and on the Layout board:
Design board: You can set a breakpoint at any location in the model where there is a step. This includes the following elements: Views (Form View, Table View, Nested View, Navigation View), Service, Modeled service, Start point, End point, Signal In, Signal Out, and Operators. For more information, see Adding or Removing a Breakpoint on the Design Board.
Layout board: You can set a breakpoint to any control that has at least one action defined for it. In case of a composite action, a breakpoint can be set on any sub action within the composite action. For more information, see Adding or Removing a Breakpoint on the Layout Board.
Breakpoints are saved between invocations of SAP NetWeaver Developer Studio. When Developer Studio opens, it loads all the basic information of each breakpoint: name, id, and the model to which it belongs. When a model is opened, its breakpoints are displayed. In addition, the Breakpoints View lists all the breakpoints you currently have set in your workspace, and enables you to disable or enable breakpoints, and add or remove breakpoints.